Fri September 13, 2013

What A Chatty Monkey May Tell Us About Learning To Talk

The gelada monkey, found only in the highlands of Ethiopia, is known as the bleeding heart baboon for the splash of red on its chest. Males of the species have a remarkable vocal agility greater than that of any nonhuman primate.

The gelada monkey, also known as the bleeding heart baboon, makes a gurgling noise or wobble sound that scientists say is close to human speech — at least in how much facial coordination it requires.

"They're smacking their lips together, they're changing their face — their facial structure — and they're vocalizing at the same time," says Morgan Gustison, a doctoral candidate and researcher with the University of Michigan Gelada Project.

So the monkey can vocalize, but is it saying anything? Gustison hopes to find out. With the help of a Young Explorers grant from the National Geographic Society, she's been going back and forth with her tape recorder to the University of Michigan gelada research site in the Simien Mountains National Park.

To research geladas, just drive into one of their habitats in the Ethiopian highlands and get out of your car. You'll find hundreds of them out in the open hills munching on grass.

They hang together in such large groups that even researchers who spend all day with the monkeys for months at a time need to code each family with letter names just to keep track of the shifting alliances.

"The J's and the K's and the D's are usually together with the V's," researcher Marcela Benitez says from her vantage point near a mountain peak. She points out different monkey families in what looks to this reporter like an indistinguishable sea of fur. "But now the D's are up there on the hill, the V's are by themselves up here, and the others are down there with the N's and the J's, which usually hang out with the M's and the A's."

Life Without Pecking Order

This fluid social order is one of the most distinctive aspects of gelada society, and one that might unlock the key to their distinctive verbal agility. Socially speaking, geladas are like the urbanites of the primate world — always bumping into strangers. "And that's actually really rare," Benitez says. "For most nonhuman primates, you know every single person in your group."

She says most nonhuman primates live in the social equivalent of the smallest of small towns, where you know everybody, and everybody knows you. There's a pecking order. Geladas, by contrast, live in massive social groups of up to 1,000 monkeys. When group size gets that large, hierarchy breaks down. So, one of the theories these scientists are testing is that geladas' vocal agility might have arisen from the necessity to quickly win over friends and allies in a crowd of strangers, like a guy on a soapbox on a street corner.

Vocal Grooming

The peaceful scene of grass-chewing monkeys one encounters on an early-morning arrival doesn't remain peaceful for long. Geladas have the longest canines per body length of any mammal, and they're not used for eating. In their daily life, conflict is simmering just under the surface. Gelada males are polygamous; one male has many females, which leaves many frustrated unattached bachelors sending threatening calls and screams from the fringes.

"I call them frat boys," Benitez says, laughing. "They look hungover, they spend a lot of time together, and then all of a sudden they decide they're going to cause problems. And everyone's afraid of them, and no one wants them around."

Complicating this ritual machismo, geladas are a female-choice society, where the females decide whom to accept or rebuff.

It's a swirl of domestic drama where fights are bound to occur, and when they do, Gustison is ready with her tape recorder. Why? Because, she says, just after a disruption of the social order is when male geladas give voice to some of their most complex strings of sound, perhaps as a way of quickly restoring relationships. "The gelada may be saying something like, 'everything's all right, I'm cool, I'm not hurt,' " says Gustison, "basically calming down the situation."

Most primates achieve this emotional bonding with physical grooming. Gustison says geladas are capable of "vocal grooming." She compares it to being thrown into a cocktail party with lots of people you barely know. The specific meaning of the words you're speaking may not be as important as the relationships you're trying to build. Indeed, "vocal grooming" may suggest something about how our earliest ancestors evolved the ability to speak.

The Big Role Of Small Talk

"It broadens our ideas about the origins of language," Gustison says. Because while much research has focused on the referential side of language, she says, language is just as much about shoring up relationships as it is about expressing information.

"I'll get off the phone with my mother, and I can't remember half the things I say, but I do know that I remember whether or not it was good conversation," Gustison says. "So we want to see besides the semantics what else is important about complex vocal communication that could be a precursor to language."

Long before our early ancestors ever formed sentences, she says, we might have been limbering up our lips, throats and tongues to send each other sounds of comfort, warning and encouragement, like we do now with babies before they learn to talk.

Under that theory, Gustison says, early man's first attempts to speak might have aimed less to describe the outside world, than simply to make that world somewhat less frightening and less lonely.

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Transcript

AUDIE CORNISH, HOST:

Lots of animals communicate. Only humans have the ability to talk as we know it. Our closest evolutionary relatives, the primates, are largely confined to grunting and a few other basic noises, except, that is, for a rather chatty monkey in Ethiopia called the gelada. As NPR's Gregory Warner reports, it's giving scientists a peek back in time. It might reveal what drove our earliest ancestors to develop their verbal agility.

(SOUNDBITE OF THE GELADA MONKEY)

GREGORY WARNER, BYLINE: This sound represents a feat of facial coordination such that no nonhuman primate can pull it off, except for a monkey known as the gelada. This particular sound...

(SOUNDBITE OF THE GELADA MONKEY)

WARNER: ...is the wabble.

MORGAN GUSTISON: OK. So what's interesting with a wabble is they're smacking their lips together, they're changing their face, their facial structure and they're vocalizing at the same time.

WARNER: I reached Morgan Gustison at her office at the University of Michigan where she's getting her PhD in biopsychology because she's writing what might be called the first ever gelada dictionary.

GUSTISON: It's kind of like a dictionary because I would love to see if strings of sounds might mean different things.

WARNER: Which is particularly difficult since those strings of sounds don't use words as we know it. And so with the help of a grant from the National Geographic Society, she's been going back and forth with her tape recorder to the only place that geladas live, high in the mountains of Ethiopia. We're like 12,000 feet up, right?

GUSTISON: 10,300.

WARNER: At their research site in the National Park, I meet Marcela Benitez, a colleague of Gustison.

MARCELA BENITEZ: Do you see them on the hill over there?

WARNER: Before I got here, my vague sense of what primate field research looked like involved a long trek through dense brush, delicately approaching a band, gradually winning their trust. Gelada research is nothing like that. You pull up in your car. You'll find hundreds of them out in the open hills munching on grass - hundreds. There's so many monkey families, the researchers have to name each family by letters and use radios to keep track.

UNIDENTIFIED WOMAN: Yes, (unintelligible)

WARNER: Which brings us to the most interesting thing about gelada society.

BENITEZ: Ds are by themselves over here. Cs are missing.

WARNER: When you have so many monkey families living in these shifting alliances...

BENITEZ: The other ones are down there with the Ns and the Js, which usually hang out with the Ms and the As.

WARNER: ...something takes place which might unlock the key to their verbal agility. Geladas are always encountering...

BENITEZ: Strangers.

WARNER: ...strangers.

BENITEZ: And that's actually really rare for most nonhuman primates, you know every single person in your group.

WARNER: There's a hierarchy.

BENITEZ: You know, he's more dominant than I am, therefore, I'm not going to fight anymore. He's really dominant. I'm going to mate with him. But if you are gelada and you live in these massive, massive social groups...

WARNER: Of up to 1,000 monkeys, that pecking order breaks down. You don't remember every face. So one of the theories these scientists are testing is that geladas use complex strings of sound rather like a guy on a soap box to quickly win over a crowd.

(SOUNDBITE OF GELADA MONKEYS)

WARNER: Now, in order to get at this question, researchers first have to learn the social dynamics. Gelada males are polygamists. One male has many females, which leaves a lot of frustrated unattached bachelors sending threatening calls from the fringes. Benitez calls them...

BENITEZ: Frat boys.

WARNER: Frat boys.

BENITEZ: They look hungover, they spend a lot of time together, and then all of a sudden they decide they're going to cause problems. And everyone's afraid of them, and no one wants them around.

WARNER: Complicating this macho ritual, geladas are a female-choice society.

BENITEZ: He's trying to copulate with her.

WARNER: So the females decide who to accept and who to rebuff. She refused him?

BENITEZ: Yep. She walked away.

WARNER: And it's not only the frat boys that start the fights.

BENITEZ: Oh, yeah. It was a group of females who started this.

WARNER: The females started this.

BENITEZ: Yep. And the females are going at it and males are coming to their females defense. And behind the As, you can see that the females are now fighting behind the males.

WARNER: Two polygamist families are facing off. There's a lot of shouting, no actual fighting yet.

WARNER: Just as that storm of aggression mysteriously passes, the male returns to his females and he delivers a soliloquy.

(SOUNDBITE OF GELADA MONKEY)

BENITEZ: So he just came back to his females and gave vocal inhale, vocal exhale, a series of moans and a vocal inhale again.

WARNER: Whatever he said, it convinced the whole family to pick up and walk off together like nothing happened.

BENITEZ: Females came along with him. Tensions are down.

WARNER: If you listen as closely as Morgan Gustison has, she's videotaped hundreds of these post conflict soliloquies, what the male gelada might be doing is...

GUSTISON: Calming down the situation.

(SOUNDBITE OF GELADA MONKEY)

GUSTISON: Saying like, oh, everything's all right, I'm cool, I'm not hurt. Yeah, just not with words, but their showing it through their song.

WARNER: She says other primates will do this post conflict reconciliation with physical grooming. But geladas seem to get in a lot of emotional bonding by vocalizing, which suggests one way that our earliest ancestors might have evolved the ability to speak.

GUSTISON: It broadens our ideas about the origins of language, so a lot of us have focused on a referential side of language.

WARNER: Being able to say, good hunting here, this mushroom poisonous and so on. But long before our earliest ancestors ever formed sentences, Gustison says we might have been limbering up our lips and throats and tongues just to send each other sounds of comfort, of warning and of encouragement like we do now with babies before they learn to talk.

GUSTISON: Because we are a social species and our relationships are important, you know, like, I'll get off the phone with my mother and I can't remember half the things I say, but I do know that, you know, I remember whether or not it was good conversation. So that's kind of the point here is we want to see, you know, well, besides the semantics, what else is important about complex vocal communication that could be kind of like a precursor of language.

WARNER: She says, early man might have taken his first steps towards language as much to represent the outside world as just to find ways to relate to each other and make that big, strange world a little bit less lonely. Gregory Warner, NPR News. Transcript provided by NPR, Copyright NPR.